Coronary artery calcium (CAC) scoring, also called a coronary calcium scan, is a test that measures the amount of calcium in the walls of the heart’s arteries.
Most of the calcium in our body is found in our bones and teeth. It helps keep them strong and healthy. But calcium in the arteries that supply the heart with oxygen and nutrients can spell trouble for our heart health.
That’s because deposits of calcium in the coronary arteries are a sign that there may also be a buildup of plaque—a waxy substance that can harden over time and narrow or block the arteries (called atherosclerosis). When this happens, it makes a heart attack or stroke more likely.
So a coronary calcium scan is one way to estimate someone’s risk of developing heart disease or having a heart attack or stroke.
This test uses a special type of imaging test called a computed tomography (CT) scan of the heart. This scan produces multiple pictures to check if calcium is present and, if so, how much.
CAC scoring may also be called:
A coronary calcium scan can help you and your clinician better understand your future risk of having a heart attack, stroke or dying from one even if you don’t have any symptoms of heart disease.
But it’s most helpful in certain cases and for certain patients.
Most of the time, results from a physical exam, bloodwork and other tests will give you and your care team enough information to gauge your future risk of a heart attack or stroke.
The test is another tool that you and your care team can use when deciding what treatment is right for you. It can help determine if there are steps you should consider taking — beyond adopting healthy lifestyle habits — to lower your risk.
CAC scoring really comes into play when there is still some doubt as to whether your risk is enough to warrant taking a statin, which is a medication that lowers cholesterol. Statins are commonly used as the first medication of choice to lower low-density lipoprotein (LDL) cholesterol, or “bad” cholesterol.
CAC scoring is not recommended if you have:
CAC scoring also shouldn’t be used to assess whether treatment is working or not.
According to the 2018 Cholesterol Guideline, CAC scoring should be used only after you and your clinician have:
The test result is given as a number, called a CAC score. It can range from 0 to over 400. Your clinician can help explain your result and what it means.
Basically, the more evidence of calcium and thickening that is seen in the inside lining of the arteries, the higher the score. The higher your CAC score, the more likely you are to develop heart disease or have an event such as a heart attack or stroke.
Keep in mind, though, this score tells us about the chance of developing disease. It’s not a guarantee. So, people with a 0 score could still have a heart attack, but the risk is very low. Similarly, people with a high CAC score aren’t certain to have a heart attack. This is why CAC scoring should be used together with other methods for estimating heart disease.
A coronary calcium scan is often done in a hospital or other medical imaging facility.
Be sure to let your clinician know if you are or could be pregnant before having this test.
It’s important to talk with your clinicians about your risk for heart disease. This way you can decide together what you can do to lower that risk.
The main risk factors for blockages in the heart’s arteries, called atherosclerotic cardiovascular disease or ASCVD include:
You may have questions about coronary calcium tests. Some common questions include: